Technical Field
The present invention relates to a liquid administration device that can help increase safety after its use.
Background Art
Prefilled syringes, which are at least partially filled with a liquid preparation in an aseptic manner and capable of administering the liquid product have been known (see JP 2005-319118 A). The prefilled syringe disclosed in JP 2005-319118 A includes a syringe outer cylinder, a gasket, the liquid preparation, and a plunger. The syringe outer cylinder has an opening part from which the liquid preparation discharges. The gasket can slide within the syringe outer cylinder. The space surrounded by the syringe outer cylinder and the gasket is filled with the liquid preparation. The plunger is coupled to the base end side of the gasket and discharges the liquid preparation from the opening part by pressing the gasket toward the tip direction. In this prefilled syringe, the opening part of the syringe outer cylinder is sealed liquid-tightly with a cap in an unused state.
When the liquid preparation is administered using the prefilled syringe, first, the cap is removed from the opening part of the syringe outer cylinder, and then, an injection needle is mounted on the opening part from which the cap is removed. Next, a living body is punctured with the injection needle, and pressing operation by the plunger is performed in this punctured state. As a result, the liquid preparation is discharged from the opening part by the gasket, thus, the liquid preparation can be administered to the living body though the injection needle. After administration, that is, after use, the prefilled syringe is disposed. In disposing this after use, the prefilled syringe is sometimes disposed while the injection needle is still mounted. In this case, there may have been a problem with erroneous puncturing by the injection needle.